Patent EA-003889-B1 (EA)
Title: Foam plastics container
Inventor: GORNELL BRIAN
IPC: B29C31/00
Filed: 2001-05-10
Abstract: 1. A method of moulding an expanded plastics container (10) having a bottom wall (11), a sidewall or sidewalls (12) extending upwardly from the bottom wall to a mouth (13) of the container, and a rim flange (14) projecting outwardly from the side walls) (12) about the container mouth (13), comprising the steps of disposing plastics material adapted for moulding an expanded product into a mould cavity (18) defining the container to be moulded with the rim flange, introducing steam into the mould cavity at the bottom wall moulding zone of the cavity to cook the plastics material and mould the expanded plastics container, and additionally directing steam into the mould cavity at or adjacent the rim flange moulding zone. 2. A method according to claim 1, wherein the expanded plastics container (10) is moulded with the mouth (13) of the container directed downwardly and its bottom wall (11) uppermost. 3. A method according to claim 1 or 2, wherein one or more cavities (21,24), which are flushed with steam to heat the mould during the cook cycle, are provided adjacent the inside and/or outside of the mould cavity (18) and the additional step of directing steam into the mould cavity adjacent the rim flange moulding zone is achieved by redirecting part of the flushing steam from one (21) of the cavities into the mould cavity at or adjacent the rim flange moulding zone. 4. A method according to claim 3, wherein said one cavity (21) for flushing steam is disposed adjacent the inside of the mould cavity and the steam is redirected from this inside cavity. 5. A method according to any preceding claim, wherein the steam directed into the mould cavity (18) at or adjacent the rim flange moulding zone is injected at a location below and closely adjacent the rim flange moulding zone. 6. A method according to any preceding claim, including the steps of disposing a laminate of flexible sheet material against a mould wall defining an external wall of the container (10) prior to disposing, in the mould cavity (18), the plastics material for moulding the expanded product, whereby the laminate is laminated to the external wall of the moulded container during the moulding cycle. 7. A method according to claim 6, wherein the laminate forms a sleeve completely surrounding the container (18) and is seated directly under the rim flange (14) of the container such that the upper edge of the laminate is concealed. 8. A mould tool for moulding an expanded plastics container (10) having a bottom wall (11), a sidewall or sidewalls (12) extending upwardly from the bottom wall to a mouth (13) of the container, and a rim flange (14) projecting outwardly from the container side wall(s) (12) about the mouth (13) of the container, said mould tool comprising male and female mould parts (16,17) which are assembled to form a mould cavity (18) defining the container having the rim flange, at least one cavity (21,24) for heating and/or cooling fluid in at least one of the mould parts adjacent the mould cavity and extending adjacent at least that part of the cavity defining the side wall(s) of the container, conduit means (25,35) for supplying steam to the heating/cooling cavity, first passageway means (28) via which steam is injected into the mould cavity and which communicates with the bottom wall moulding zone of the mould cavity, second passageway means (41-47) for directing a portion of the flushing steam from the heating/cooling cavity into the mould cavity at or adjacent the rim flange moulding zone of the mould cavity, and valve means (50) for controlling flow of steam via said second passage means. 9. A mould tool according to claim 8, wherein both mould parts (16,17) have heating/cooling cavities (21,24) substantially coextensive with at least that wall of the mould part moulding the side wall(s) (12) of the container. 10. A mould tool according to claim 8 or 9, wherein the heating/cooling cavity (21) of the male mould part (16) is connectable via the second passageway means (41-47) to the mould cavity (18) at a position adjacent the rim flange moulding. 11. A mould tool according to claim 8, wherein the male mould part (16) has a heating/cooling cavity (21) adjacent the mould cavity (18) and substantially coextensive with at least that part of the moulded cavity defining the side wall(s) (12) of the container, the conduit means (25) is connectable under control of second valve means (30) to the first passageway means (28) and the heating/cooling cavity (21) in the male mould part is connectable via the second passageway means (41-47) to the mould cavity at a position adjacent the rim flange moulding zone. 12. A mould tool according to claim 8, 9, 10 or 11, wherein the male mould part (16) comprises a core section (19) and an outer shell fitted over the core section so as to provide a heating/cooling cavity (21) within the outer shell, the outer surface of the outer shell moulding the internal surface of the container (10). 13. A mould tool according to any preceding claim 8 to 12, wherein the female mould part (17) comprises an inner female shell (22) which moulds the external wall of the container (10) and a top mould member (23) fitted over the outside of the female shell so as to provide a heating/cooling cavity (24) substantially coextensive with the female shell and about the outside of the mould cavity (18). 14. A mould tool according to any preceding claim 8 to 13, wherein each passageway means (28,46) is connected via an annular groove (29,47) in the moulding surface of the relevant mould part (16,17) to assist distribution of the steam about the mould cavity (18), and a flexible ring seal (33,49) is located within the annular groove, said ring seat being profiled so as to allow steam under pressure to pass over the seal into the mould cavity and prevent the ingress of moulding material. 15. A mould tool according to any preceding claim 8 to 14, wherein the female mould part (17) is separable from the male mould part (16) to permit removal of the moulded container (10) and the female mould part includes means (54) adjacent the bottom of the container for applying air pressure to the bottom of the container as the mould parts are separated in order to cause the moulded container (10) to be retained on the male mould part (16), and the male mould part includes means (31,32) for applying air pressure to the inside of the bottom of the container (10) in order to eject the moulded container from the male mould part.